1. Field of the Invention
Embodiments of the invention relate to a touch screen panel.
2. Discussion of the Related Art
Along with the development of the electronics industry, display devices, such as a liquid crystal display, an electroluminescent display, and a plasma display panel, having a fast response time, low power consumption, and an excellent color reproduction rate, have been in the spotlight. The display devices are used for various electronic products such as televisions, monitors for computers, notebook computers, mobile telephones, display units for refrigerators, personal digital assistants, automated teller machines, and the like. In general, the display device interfaces with various input devices such as a keyboard, a mouse, and a digitizer. However, when a separate input device such as a keyboard, a mouse, or digitizer is used, user's dissatisfaction is increased because the user is required to know how to use the separate input device and the separate input device occupies space. Therefore, a convenient and simple input device that can reduce erroneous operation is needed. Also, there is a need for a touch screen panel in which the user can input information by directly contacting a screen with user's finger or a pen.
Because the touch screen panel has a simple configuration, which minimizes erroneous operations, the user can perform an input action without using a separate input device, and can quickly and easily manipulate through contents displayed on the screen. Accordingly, the touch screen panel has been applied to various display devices.
Touch screen panels are classified into a resistive type, a capacitive type, and an electromagnetic type based on a detection method of a touched portion. The resistive type touch screen panel determines a touched position by a voltage gradient based on changes of resistance in a state where a DC voltage is applied to metal electrodes formed on an upper plate or a lower plate. The capacitive type touch screen panel senses a touched position based on changes in capacitance generated in an upper or lower plate when the user physically contacts with a conductive film formed on the upper or lower plate. The electromagnetic type touch screen panel detects a touched portion by reading an LC value induced as an electromagnetic pen touches a conductive film.
Hereinafter, a related art capacitive type touch screen panel will be described with reference to FIG. 1. FIG. 1 is a plan view of a related art capacitive type touch screen panel.
As shown in FIG. 1, the related art capacitive type touch screen panel includes an electrode forming part A, a routing wire forming part B, and a pad forming part C.
The electrode forming part A is formed on a substrate 10. The electrode forming part A includes a plurality of first electrodes 21 arranged in parallel in a first direction (for example, X-axis direction) and a plurality of second electrodes 22 arranged in a second direction (for example, Y-axis direction) perpendicular to the first direction to cross over the first electrodes 21. Although the first electrodes 21 and the second electrodes 22 cross over each other, they are kept electrically insulated by an insulation layer (not shown). Moreover, the adjacent first electrodes 21 are separated from each other, but are connected to each other by bridges 41, thereby forming first channels in a row direction. Namely, the bridges 41 connect the adjacent first electrodes 21 to each other through contact holes 30a and 30b formed in the insulation layer (not shown) covered on the top of the first and second electrodes 21 and 22, whereby the first channels each having the first electrodes 21 connected together are formed in the row direction. Further, the second electrodes 22 are integrally formed, thereby forming second channels crossing over the first channels in a column direction.
The routing wire forming part B is formed outside the electrode forming part A. The routing wire forming part B includes a plurality of first routing wires 42 respectively connected to the plurality of first electrodes 21 and a plurality of second routing wires 43 respectively connected to the plurality of second electrodes 22.
The pad forming part C includes a plurality of first pads 61 respectively connected to the plurality of first electrodes 21 through the plurality of first routing wires 42 and a plurality of second pads 62 respectively connected to the plurality of second electrodes 22 through the plurality of second routing wires 43.
In the capacitive type touch screen panel having the above-described configuration, it is necessary to test whether or not the first channel of the row direction and the second channel of the column direction are shorted to each other or whether or not each of the first channel and the second channel is opened. This test is referred to as a channel open/short test. The channel open/short test generally includes an array test conducted after the touch screen panel is manufactured and an image test conducted after the touch screen panel is applied to the display device. A test equipment is used to conduct the channel open/short test. However, because the test equipment may cause static electricity, a countermeasure for preventing the static electricity is necessary.
In order to preventing the static electricity, it is necessary to incorporate a separate antistatic circuit into the touch screen panel. Accordingly, an additional process has to be performed so as to form the antistatic circuit, and a space to form the antistatic circuit is necessary. Furthermore, when the array test and/or the image test are conducted using the first and second pads 61 and 62 of the pad forming part C, it is decided whether or not each of the first and second channels is normal by contacting a signal supplying pin for supplying a signal with each of the first and second pads 61 and 62 respectively corresponding to the first and second channels, and then contacting a signal receiving pin with each of the first and second pads which is contacted with the signal application pin. However, because the above-described process for the channel open/short test has to be performed on each of the first and second channels, much time is consumed. As a result, a tact time (indicating a time required to manufacture a unit product so as to meet its daily production target) increases, and the manufacturing yield is reduced.